1. Field of the Invention
The present invention relates to personal computers, and more particularly to devices and methods for conductively dissipating heat generated from operational internal electronic circuitry and/or components (e.g., microprocessors) of personal computers, to an environment external to the personal computer.
2. Description of the Related Art
Consumers typically prefer to obtain personal computers (PCs) having a higher-speed processor, more compact dimension, improved portability, and/or an overall lighter weight (e.g., IBM® models 560, T20; IBM is a registered trademark of International Business Machines, Armonk, N.Y., USA). To meet demands, PC designers often strive to economically offer added computational functionality to model designs by integrating higher-speed processors and optimizing the internal platform, components, and/or operating systems to provide a consumer enhanced performance capabilities in a more compact model. Consequently, designers desire to better the overall portability and compactness of each PC model introduced.
In accordance with recent technical developments, various types of PCs, such as desktops, towers, laptops, notebooks, and portable types, have been developed and are being sold on the market. Additionally, other portable computer-based devices such as processor-based communicators and portable information terminals (PITs) (e.g., Personal Assistants, hand-held digital notepads, and Personal Digital Assistants (PDAs)) are also being developed and sold in the marketplace with similar consumer interest and demand. Critical in the design considerations for these processor-based devices is improving dimensional slimness, optimizing portability, minimizing the production cost, and reducing overall weight while integrating higher-speed processors to provide a user with additional functionality. In particular, efficiently removing heat energy generated by heat-generating components, power supplies and other sources within the device, has proved difficult but is required to ensure satisfactory operation of a higher-speed processor-based device.
As used herein, the term “personal computer” includes any electronic data processing device having a central processing unit (CPU) (e.g. microprocessor) including but not limited to devices such as: a computer, PC, computing device, communicator and PIT, wherein for the general purposes herein, it is desirable for such a device to be dimensionally portable.
As used herein, the term “eat-generating source” is any source within a personal computer which generates heat energy during its operation, including but not limited to an electrical element, electronic component, resident internal device, and power source.
However, it is known that as a processor's operating speed (i.e., frequency) increases so does the power consumption by (i.e., input power to the processor) and the surface temperature of the processor. As such, there is typically a substantial increase in the power required to operate a higher-speed processor and there is a need for additional cooling of heat generated by the processor over existing known methods to maintain the junction temperature of the processor to be within acceptable limits.
For example, an INTEL® mobile zPIII processor consumes approximately 12 Watts and has a junction temperature of 212 degrees Fahrenheit at its optimal operational frequency of 500 MHz (INTEL is a registered trademark of ITEL Corporation, Santa Clara, Calif., USA). An INTEL mobile PIII processor consumes approximately 20 Watts and has a junction temperature of 212 degrees Fahrenheit at its optimal operational frequency of 600 MHz. Analogously, it is believed that next-generation processors may operate at optimal processing speeds of about 1 Ghz and greater, and require approximately 25 Watts of power and greater, while having operational junction temperatures of about 212 degrees Fahrenheit.
To overcome the heat generated by a processor, an internal conventional cooling system (CCS) is often integrated within a personal computer to dissipate heat and cool the surface of the processor. For instance, it is known to air-cool a low-speed processor or deploy an internal heat sink apparatus such as a heat pipe to cool a mid-speed processor. With mid to high-speed processors, it is known to internally mount one or more thermoelectric cooling devices (TECs) which, as used herein, typically are solid state heat pumps based on the Peltier effect and also include but are not limited to motorized fans, fan sinks, heat sinks, spreader plates, heat pipes, Peltier devices, and other similar conventional thermodynamic dissipating device, singularly or in combination, which operate to reduce the junction temperature of the processor by removing excess beat through conductive means. It is known that a CCS may comprise one or more TEC devices in a typical arrangement for dissipating heat from a heat-generating source (e.g., operating processor) for distribution within or external to the computer housing (e.g., internal environment).
Traditionally, precise thermal contact between the heat-generating component and a CCS is required for efficient heat transfer. In a conventional application, pressure mounts are often utilized to secure a surface of the CCS contact with a surface of the processor.
FIG. 1 shows an exemplary CCS 100 in which TEC 110 is mounted on processor 120 within housing 130 of personal computer 140., wherein heat is dissipated across internal ambient environment 150 of personal computer 140.
Typically, TEC 110 mounted on processor 120 collects heat generated by processor 120 and dissipates the collected heat to heat sink 160 wherein the heat sink thereafter dissipates the heated air within 150 or external to the computer 140 at 180 via a motorized fan 170. Since the amount of heat which may be dissipated is proportional to the size and location of the TEC and to the heat generated by the internal processor, often the dimensions of the TEC are increased to improve the amount of heat dissipated.
CCSs will likely prove inadequate in satisfactorily dissipating the additional heat generated by higher-speed processors, as there is often either insufficient free-space for heat dissipation within the personal computer and/or the cooling system components are undersized with respect to the thermodynamic characteristics of the higher-speed processor. It is also foreseeable that TECs and CCSs that are improperly sized or have inadequate air flow available, may fail due to increased condensation during operation within the personal computer. As a result, utilizing a CCS in certain slim computer designs having higher-speed processors may no longer be feasible and a CCS may not therefore provide adequate cooling for future slim personal computer designs having higher-speed processors.
Similarly, since CCSs continuously consume power from their personal computer host, the CCS's power consumption in combination with the added power demands from the higher-speed processor may either exceed the available power or detrimentally reduce the utilization of a portable power source. Increasing the available power from a portable power source is typically not a preferred solution since both size and weight of the power source would typically be increased.
Therefore, designers have often been limited in their ability to economically balance the physical size and weight of a personal computer with the increased thermodynamic effects and power requirements of an integrated higher-speed processor. Consequently, designers may often attempt to resolve design issues by conducting one of the following less desirable design approaches: 1) increasing a casing's dimensions to account for increased thermodynamic effects and power requirements of a higher-speed processor; 2) minimizing changes to existing casing's dimension and portable power supply, thereby limiting the selection of an integrated higher-speed processor to reduced parameters (i.e., non-op zed processor having reduced functionality); 3) minimizing changes to existing casing dimensions by reducing functionality to reduce power (also known as “throttling”) to the integrated processor such that the processor operates at a slower speed and generates less heat than at optimal speed; 4) adding costs to the personal computer by using more expensive materials, denser electronics and similar; or 5) a combination of any of the preceding approaches.
With the advent of higher-speed processors, it is projected that the overlap between the maximum operating temperature limit of the internal processors will exceed the temperature design margins of current compact personal computer designs. Similarly, with the projected increase in power requirements needed to operate the higher-speed processors, it is expected that the weight of the personal computer will increase, due to additional equipment, and that the placement of the additional equipment will virtually eliminate or exceed the available internal free-space. Additionally, since conventional heat dissipation techniques operate continuously, it is likely that the slim personal computer designs will be unable to accommodate higher-speed processors and CCSs without sacrificing dimensional compactness and portability. As a result, given the growing consumer demands to further reduce the dimensional size and weight of the personal computer while increasing functionality, integrating higher-speed processors into more portable and compact personal computer designs remains at risk.